There are many failures that can happen when protecting Hyper-V hosts and CSV’s that are a result of the Cluster network configuration not being optimized for redirected mode communication. In most cases these problems will only happen under a heavy load, and when it happens we can lose access to the storage that houses the CSV, Virtual machines may reboot or backups may simply fail.

The following errors codes will be logged on the DPM server when the Cluster network configuration is not optimized. These error codes assume that you have already installed Service Pack 1 for Windows Server 2008 R2. Install it to get the available VSS and Hyper-V component updates.

ErrorCode: 0x8007173D (-2147018947): Back up is in progress. Please wait for backup completion before trying this operation again.

ErrorCode: 0xC000020C (-1073741300): The specified network name is no longer available.

ErrorCode: 0x80042308 (-2147212536): VSS_E_OBJECT_NOT_FOUND: The specified object was not found.

ErrorCode: 0x8007274C (-2147014836): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.

The first step in addressing these errors is to use the following KB article to verify that the Cluster network configuration is configured as expected:

Attempting to utilize a single network adapter for all traffic will quickly expose these problems. More commonly, a separate Live Migration network will not be setup and used, thus the network will quickly become saturated.

There are also post SP1 hotfixes available that will resolve many of the network communication problems:

2263829: The network connection of a running Hyper-V virtual machine may be lost under heavy outgoing network traffic on a computer that is running Windows Server 2008 R2 SP1 (http://support.microsoft.com/kb/2263829)